Projector.



J. MINOR.

PROJECTOR.

APPLIoATIN FILED 1320.5, 1907.

9|| IIIOI l llzl OAIIIIMFMI Patented Dec.22, 1908.

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NITED STATES PATENT OFFICE.

JOHN MINOR, OF LEXINGTON, KENTUCKY.

PROJECTOR.

To all whom it may concern.'

Be it known that I, JOHN MINOR, a citizen of the United States, residingat Lexington, in the county of Fayette and State of Kentucky, haveinvented certain new and useful Improvements in Projectors, of which thefollowing is a specification.

This invention relates to measuring instruments, and has for its objectto provide a protractor of simple design, for use by carpenters,builders, architects, in schools, etc.

Another object is to provide such an article which will simplify theoperation of discovering the proper length for certain timbers and theangle at which they should be cut, in the construction of roofs,bridges, etc.

Another object is to provide an attachment which may be fitted tocarpenters rules of the pivoted type to convert them into protractors.

Another object is to provide such an article which will be low in costand easy to manufacture.

Other objects and advantages will be apparent from the accompanyingdescription, and it Will be understood that changes in the specific formshown and described may be made within the scope of the claims withoutdeparting from the spirit of the invention.

In the drawings forming a part of this specification, and in which likenumerals of reference indicate similar parts in the several views,Figure 1 is a plan view of the instrument, Fig. 2 is a sectional viewhorizontally, showing the pivotal engagement of the horizontal andhypotenuse sections, and Fig. 3 is a similar view, showing the means forengaging the vertical section on the horizontal section.

Referring now to the drawings, there is shown a protractor made ofmetal, wood, or other suitable material, having a horizontal section 10,a hypotenuse section 11 pivoted thereon, and a vertical section 12slidably engaged on the horizontal section. Each of the sections namedhas marked thereon a suitable series of scales for indicating units oflength. V

The horizontal section 1() comprises a straight-edge, or rule, having asemicircular knob 18 extending laterally therefrom at one end, in whichthere is a perforation 14, for a purpose to be indicated. The hypotenusesection 11 is formed similarly to the section 10, having a knob 13 and aperforation 14, and is secured pivotally upon the section 10 Specicationof Letters Patent.

Application filed December 5, 1907.

Patented Dec. 22, 1908.

Serial N0. 405,243.

by means of a threaded bolt 15 engaged through the perforations 14 and111 and a Washer 16. A wing-nut 16 is engaged over the projecting end ofthe bolt 15 and is arranged to engage against the washer to hold thesections 10 and 11 rigidly against movement when they have been adjustedat the desired angle.

The vertical section 12 comprises a straight ruler, provided with alaterally extending recess 17 at its lower end having a shoulder 18 atits inner side and a wall 19 at its outer side, and having an inwardlyextending armpiece 2() secured upon the wall 19 by means of screws 19with its end edge 20 in spaced relation with the shoulder 1S, for apurpose to be indicated. The horizontal section 10` is engaged slidablyin the recess 17 beneath the arm 20, the figures of the scale on thehorizontal section being observable in the space between the shoulder 18and the edge 20 of the arm 20. A thumb-screw 21 is engaged through athreaded opening 22 in the wall 19 of the recess 17, being arranged tobear against the horizontal section 10 to hold the vertical sectionadjustably at any point in the length of the horizontal section.

In use, for planning and constructing the wooden framework for a roof,it is only necessary to determine the pitch which the roof shall haveand set the hypotenuse section 11 at a corresponding angle to thehorizontal section 10, then move the vertical section 12 to the properpoint on the horizontal section, when the pro er length for certaintimbers required wil be indicated to scale at the junction of thesections. rI`he an 'le at which the ends of the timbers should e cut isalso indicated, and by placing the instrument upon one of such timbersit will serve as a guide for marking the line on which it should be cut.In order to obtain the pitch of the roof, it is necessary to determinethe total rise to be given any portion of the roof, and the distancefrom the eaves at which the apex shall be, and setting the vertical andhypotenuse sections in corresponding adjustment. riherea'fter, if theroofs shall have L extensions or other extensions, the length ofnecessary beams may be obtained by adjustment of the vertical sectionalone, retaining the hypotenuse section at the angle originallypresented. The use of this protractor for other work in buildingconstruction, bridge work, etc., is similar to the application abovedescribed,

When not in use, the vertical section 12 may be disengaged from thehorizontal section and the hypotenuse section l 1 folded to lieadjacently parallel to the horizontal section, and

5 the parts disposed in the pocket, or otherwise,

conveniently for carrying. It will be seen that by means of the recess17 and thumbscrew 21 the vertical section 12 may be attached to ordinaryrulers to form right- 170 angle squares, and to rulers of the foldingtype to form protractors, similar to applicants complete invention.

What is claimed is:

1. In a measuring device, the combina tion with straight edged sectionsconnected pivotally, and having scales marked thereon at one edge, of astraight edged member having a transverse recess therein at one end,opening through the opposite edges of the member, and a retaining armsecured to the member outwardly of the recess and projecting inwardlythereover, the inner end of the arm being disposed in spaced'relationwith the inner edge of the recess, said recess 25 having one of saidfirst named sections recess to lie with its inner edge in spacedrelation with the inner edge of said recess, said recess being adaptedto receive a ruler siidably therein having a scale marked upon one edgethereof, to expose said scale to view inwardly of the retaining member,and a headed screw engaged through the outer end portion of the firstnamed member and adapted to impinge against a ruler carried within therecess.

In testimony whereof I afliX my signature, n

in presence of two witnesses.

JOHN MINOR. Witnesses:

ToM MGMEEKIN, E. WHrrsoN.

